1. The Field of the Invention
The present invention is related to a utility table, and more particularly, to a lightweight folding table having legs attached in self-fixturing fashion.
2. Technical Background
Lightweight folding tables are indispensable for groups or organizations that have limited floor space usable for multiple purposes. For example, foldable utility tables can be placed in a pre-determined configuration to meet the space requirements of a school or community gymnasium, a church multi-purpose room, or a hotel conference meeting room. Afterward, the tables can be neatly stored away and the room used for a different purpose. Thus, lightweight folding tables allow a group or organization to maximize the efficiency and utility of a particular space.
Foldable utility tables can also provide an immediate temporary work space in a garage, tool shed, and the like. The portability and foldability of these utility tables allows a user to conveniently set up, take down, and store the table whenever and wherever the user chooses.
A major drawback with many lightweight folding tables of the prior art is their inherent size and bulkiness. Many such utility tables require two people to collapse and store the table after use. Moreover, some prior art lightweight folding tables are heavy enough to cause injury if dropped or mishandled. These unwieldy tables are usually made from hardwood, particle board, or similarly heavy materials. In an attempt to overcome this bulkiness problem, some prior art portable utility tables are formed of lighter-weight materials. However, many of these utility tables generally lack the sturdiness of the heavier-weight prior art utility tables.
Another disadvantage to many prior art utility tables is the means used for attaching the table legs or two or more support pedestals to the underside of the table. As will be appreciated, prior art table legs are typically attached to the table top using mechanical fasteners, such as threaded screws or bolts, that are drilled into the underside of the table top. This means of attachment may compromise the integrity of the table top, thereby making it weaker at the point of attachment between the table legs and the table top.
Weakening of the table top material is especially problematic if lightweight materials are used to construct the tabletop. If legs are independently attached, as with smaller folding tables such as card tables, the danger of deflection of the table top may be increased because each leg is subject to lateral, or sideways, forces in multiple directions. With smaller tables, members used to attach the legs to the table top must also be compact, and thus may not effectively spread forces against the leg over a large region of the table top. In effect, forces against a leg are concentrated in the small region where the leg and any attachment members are affixed to the table top. As a result, the table top may bend, or the leg may become dislodged from the attachment members.
Many lightweight prior art tables compensate for the weakness of the lightweight table top material by adding a frame of stronger material underneath the table top. Such frames are typically made of metal, and add considerably to the weight of the table, to the extent that the table may no longer reasonably be classified as a lightweight table. Furthermore, additional parts are required to attach the frame to the table top. Tables with separate frames typically have legs that are not independently attached. In effect, the legs are attached to a separate, common member, such as the frame, which is then attached to the table top. Hence, extra steps are required to attach the legs to the table top.
In addition, mechanical fasteners tend to increase the number of parts required for a table. If any significant amount of friction is anticipated between a metal fastener and a plastic part, a bushing, bearing, or similar device must be used to insulate the plastic part from wear. Thus, it is especially desirable to avoid the use of mechanical fasteners between metal and plastic parts.
Prior art methods for attaching legs typically also require several steps to complete the attachment. For example, with many prior art tables, each leg must first be positioned against the underside of the table. Then, the leg must be fixtured, or held in proper alignment with the contact surface on the table top while fasteners are applied.
Fixturing often involves the use of multiple machines, in the case of an automated process, because one machine must hold the leg and the table top together, while another machine completes the fastening process. In the case of human assembly, one person must often keep the leg and table top together while another applies the fastening method. If a single person holds the leg and table top together, he or she must attach the table top and leg together while holding them. Such a process is often difficult to carry out rapidly without making errors. Alternatively, extra implements, such as clamps, clips, temporary mechanical fasteners, and the like may be applied prior to fastening and then removed once fastening has been carried out.
The need to fixture the table and legs adds dramatically to the time required to assemble the table, as well as the amount of equipment and employees needed. Fixturing is especially problematic when mechanical fasteners are used, because mating surfaces, such as bolts, threaded openings, and the like must be precisely aligned. Added steps in the assembly process also increase the chances that a mistake will be made, and the table improperly constructed.
From the foregoing, it will be appreciated that it would be an advancement in the art to provide a lightweight folding table that is durable enough to withstand the increased wear and tear that portable utility tables are subjected to over long periods of time and sturdy enough to support varying sized loads that will be place on the table, while at the same time being light-weight enough to be easily set up and taken down.
It would be another advancement in the art to provide a lightweight folding table that does not require extra process steps, machinery, or personnel to carry out fixturing of the legs to the table top for attachment. It would be a further advancement in the art to provide a lightweight folding table having a leg or support pedestal attachment mechanism that does not require any mechanical fasteners attached to the table top.
Yet further, it would be an advancement in the art to provide a method and apparatus for attaching legs to a table top that would not require occupation of a great deal of mounting space, and that would permit independent attachment and folding of the legs. The method and apparatus could then be effectively used with smaller tables, such as card tables.
Such a lightweight folding table is disclosed and claimed herein.
The present invention is directed to a novel lightweight folding table having legs that are independently attached to a table top, preferably without the use of a frame or any additional mechanical fasteners. The table top maybe constructed of a lightweight material, such as a plastic, and may be made from an inexpensive and rapid process, such as blow molding. In one presently preferred embodiment, the table top includes a mounting surface and a working surface formed opposite the mounting surface. Preferably, each leg is pivotally mounted on the table top so that the legs may be folded against the table top for storage and transportation of the table. Each leg may fold in a different direction so that no two legs overlap.
Brackets may be provided to attach the legs to the table top. More specifically, each leg may be pivotally attached to a bracket, and each bracket may, in turn, be rigidly affixed to the mounting surface. The brackets are preferably made from a comparatively stiff, strong material, such as a metal. Preferably, the brackets are shaped to distribute lateral stresses against the legs over a comparatively large portion of the mounting surface, so that deflection of the table top does not occur.
Other members may be attached between the brackets and the legs to provide additional stability and locking in the unfolded and/or folded positions. For example, a slotted member and a support strut may be attached between the leg and the bracket. A knob, wingnut, or other similar tightening device may be threaded through the slot and a suitable opening in the leg to enable a user to lock the leg in a desired orientation.
A fixturing mount is preferably formed in the mounting surface for each bracket. The fixturing mount may include one or more fixturing protrusions, formed integrally with the table top, that are positioned to keep the bracket in place. For example, a mounting shelf may enclose all of the legs, and may form a fixturing protrusion in all of the fixturing mounts. Each fixturing mount may also have additional fixturing protrusions in the form of a first abutment positioned to restrict motion of the bracket in one lateral direction (a direction parallel to the table top) and a second abutment positioned to restrict motion of the bracket in a second lateral direction.
Other fixturing protrusions outside the fixturing mounts may also be used. For example, an upraised portion, in the form of a centrally located plateau, may be formed on the mounting surface. Each leg may be arranged so as to lay flat against one side of the plateau when the table is in the folded configuration. A securing member may be formed near each side of the plateau, so that each folded leg is engaged between the plateau and a securing member.
The fixturing protrusions may thus provide an effective guide for assembly of the brackets with the table top. Furthermore, the fixturing protrusions may be configured to fixture the brackets to the mounting surface for attachment. For example, the abutments may be formed in close proximity to the mounting shelf so that the bracket is held between the abutments and the mounting shelfby friction. Similarly, the securing members mayhold the legs against the plateau. Thus, the brackets may be effectively held in place once they are assembled, so that no additional fixturing steps need be taken. Recesses may also be formed in the mounting shelf with gaps designed to engage tabs protruding from the brackets, to provide additional holding or fixturing force. The brackets may then be attached to the mounting surface by any chosen method.
The fixturing provided by the fixturing protrusions is ideal for use with adhesive attachment, because the adhesive may be allowed to set with no further necessary steps. Thus, although the present invention may provide fixturing for mechanical fasteners, the fixturing action of the present invention provides unique benefits when used with an adhesive. Additional features may be used to facilitate application and setting of the adhesive. For example, slots may be formed in the fixturing protrusions to accommodate the adhesive and hold it next to the brackets, so that a tighter bond is formed.
From the foregoing, it will be appreciated that the present invention provides a lightweight folding table that is inexpensive and easy to manufacture, and yet lightweight and durable. The present invention also provides a method of attaching independent legs to a table top through the use of self-fixturing retaining structures, or fixturing mounts. The fixturing mounts help reduce the time, machinery, and personnel required for assembly of a table.
Furthermore, the table top design of the present invention permits effective use of adhesives to replace conventional mechanical fasteners, so that the part count and assembly time are further reduced. The present invention facilitates independent attachment of the legs so that smaller tables may be easily produced without sacrificing sturdiness. The foregoing and other advantages and features of the present invention will become more filly apparent by examination of the following description of the presently preferred embodiments and appended claims, taken in conjunction with the accompanying drawings.